netlink.c revision 02f5daa563456c1ff3c3422aa3ec00e67460f762 
1/*
2 * Netlink event notifications for SELinux.
3 *
4 * Author: James Morris <jmorris@redhat.com>
5 *
6 * Copyright (C) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2,
10 * as published by the Free Software Foundation.
11 */
12#include <linux/init.h>
13#include <linux/types.h>
14#include <linux/slab.h>
15#include <linux/stddef.h>
16#include <linux/kernel.h>
17#include <linux/skbuff.h>
18#include <linux/netlink.h>
19#include <linux/selinux_netlink.h>
20#include <net/net_namespace.h>
21
22#include "security.h"
23
24static struct sock *selnl;
25
26static int selnl_msglen(int msgtype)
27{
28	int ret = 0;
29
30	switch (msgtype) {
31	case SELNL_MSG_SETENFORCE:
32		ret = sizeof(struct selnl_msg_setenforce);
33		break;
34
35	case SELNL_MSG_POLICYLOAD:
36		ret = sizeof(struct selnl_msg_policyload);
37		break;
38
39	default:
40		BUG();
41	}
42	return ret;
43}
44
45static void selnl_add_payload(struct nlmsghdr *nlh, int len, int msgtype, void *data)
46{
47	switch (msgtype) {
48	case SELNL_MSG_SETENFORCE: {
49		struct selnl_msg_setenforce *msg = NLMSG_DATA(nlh);
50
51		memset(msg, 0, len);
52		msg->val = *((int *)data);
53		break;
54	}
55
56	case SELNL_MSG_POLICYLOAD: {
57		struct selnl_msg_policyload *msg = NLMSG_DATA(nlh);
58
59		memset(msg, 0, len);
60		msg->seqno = *((u32 *)data);
61		break;
62	}
63
64	default:
65		BUG();
66	}
67}
68
69static void selnl_notify(int msgtype, void *data)
70{
71	int len;
72	sk_buff_data_t tmp;
73	struct sk_buff *skb;
74	struct nlmsghdr *nlh;
75
76	len = selnl_msglen(msgtype);
77
78	skb = alloc_skb(NLMSG_SPACE(len), GFP_USER);
79	if (!skb)
80		goto oom;
81
82	tmp = skb->tail;
83	nlh = NLMSG_PUT(skb, 0, 0, msgtype, len);
84	selnl_add_payload(nlh, len, msgtype, data);
85	nlh->nlmsg_len = skb->tail - tmp;
86	NETLINK_CB(skb).dst_group = SELNLGRP_AVC;
87	netlink_broadcast(selnl, skb, 0, SELNLGRP_AVC, GFP_USER);
88out:
89	return;
90
91nlmsg_failure:
92	kfree_skb(skb);
93oom:
94	printk(KERN_ERR "SELinux:  OOM in %s\n", __func__);
95	goto out;
96}
97
98void selnl_notify_setenforce(int val)
99{
100	selnl_notify(SELNL_MSG_SETENFORCE, &val);
101}
102
103void selnl_notify_policyload(u32 seqno)
104{
105	selnl_notify(SELNL_MSG_POLICYLOAD, &seqno);
106}
107
108static int __init selnl_init(void)
109{
110	selnl = netlink_kernel_create(&init_net, NETLINK_SELINUX,
111				      SELNLGRP_MAX, NULL, NULL, THIS_MODULE);
112	if (selnl == NULL)
113		panic("SELinux:  Cannot create netlink socket.");
114	netlink_set_nonroot(NETLINK_SELINUX, NL_NONROOT_RECV);
115	return 0;
116}
117
118__initcall(selnl_init);
119